flyby function

x=linspace(0.001, 3, 300);

y=besselj(5,sqrt(1+x.^2));
m=exp(5*i*atan(x.^-1));
z=y.*m;
plot(x,log(z),'r');
hold on;
plot(x,log(real(z)),'k')
hold on;
plot(x,log(imag(z)),'b:')
hold off;